Why does the stability of hydrides decrease down the group?

The stability of hydrides decreases down the group from NH3 to BiH3. This is due to a decrease in their bond dissociation enthalpy. Stability decreases down the group as the bond dissociation energy decreases. Hence, the bond dissociation energy decreases down the group due to the increase in the central atom size.

What are the properties of covalent hydride?

Covalent hydrides are liquids or gases that have low melting and boiling points, except in those cases (such as water) where their properties are modified by hydrogen bonding. For example, although volatile, NH3, H2O, and HF are held together in the liquid state primarily by hydrogen bonding.

How do thermal stability vary down a group of hydrides?

Answer: The thermal stability of the hydrides of group 16 elements decreases down the group, i.e., H2O > H2S > H2Se > H2Te > H2Po. This is because M-H bond dissociation energy decreases down the group with the increase in the size of central atom.

Is hydride ion stable?

Hydride ions are extremely unstable reducing species. They abstract protons from water and other protic solvents and combine to make H2 gas and a hydroxide ion.

Why are covalent hydrides volatile?

Most nonmetal hydrides, for example, are volatile compounds kept together in the condensed state by weak intermolecular van der Waals interactions. In these covalent hydrides examples, molecules are kept together in the liquid state, generally existing mainly by hydrogen bonded form, despite their volatile nature.

Why does thermal stability of alkali metal hydride decreases down the group?

Thermal stability of hydrides of first group elements follows the order- A] LiH>NaH>KH>RbH. When we move down the group the size of alkali metals increase and nuclear charge decreases due to which the force of attraction between the nucleus and outermost shell decreases. Hence the bond dissociation energy decreases .

Why does reducing character increases from NH3 to BiH3?

The reducing character depends on the stability of the hydride. The greater the instability of a hydride, the greater is its reducing character. Because the stability decreases from NH3 to BiH3, the reducing character increases.

Why are hydrides polar?

These hydrides all have a bent shape due to the two lone pair of electrons on the central atom. This makes the molecules polar and due to an uneven charge distribution. The number of electrons increases, which increases the London dispersion between the molecules. .

Why does thermal stability decrease across period?

Smaller is the size of cation, more will be the covalent character in the molecule. Size of elements decreases across the period.

Why do hydrides decrease in stability down the group?

This is due to the fact size of atom increases down the group which leads to weaker interaction between atoms and its hydride leading to decrease in stability down the group.

Why does a hydride become more and more covalent over time?

The metallic character of elements drops moving across the periods, therefore a hydride becomes more and more covalent as the element H is bonded to is located more to the right. What does Google know about me? You may know that Google is tracking you, but most people don’t realize the extent of it.

Why does the stability of hydrides decrease from ammonia to bismuthine?

The stability of hydrides decreases from ammonia to bismuthine. This is because the central atom E increases in size down the group. With the increase in the size of the central atom, the E – H bond becomes weaker. where E is nitrogen ,phosphorus, arsenic,antimony , bismuth.

How does the size of the central atom affect E-H bonds?

This is because the central atom E increases in size down the group. With the increase in the size of the central atom, the E – H bond becomes weaker. where E is nitrogen ,phosphorus, arsenic,antimony , bismuth. With the increase in size, the overlapping between the orbitals of E and hydrogen will not be effective.